Error recovery message improvements

Author: sharadraju

doc/src/release_notes.rst

@@ -17,6 +17,9 @@ Thin Mode Changes
     response that spans multiple packets. This break could occur due to a
     server error, the session being killed or a call to `breakExecution()`.
 
+#)  Improve error message when an internal error handler fails and a connection
+    is no longer usable.
+
 node-oracledb `v6.0.2 <https://github.com/oracle/node-oracledb/compare/v6.0.1...v6.0.2>`__ (27 Jun 2023)
 --------------------------------------------------------------------------------------------------------
 

lib/thin/protocol/protocol.js

@@ -111,7 +111,7 @@ class Protocol {
     this.writeBuf.endRequest();
   }
 
-  async _recoverFromError(message) {
+  async _recoverFromError(caughtErr, message) {
     /*
      * We have NJS error(protocol related) detected during packet write/read
      * operation.  Issue a break and reset to clear channel . We receive the
@@ -124,10 +124,12 @@ class Protocol {
       await this.readBuf.waitForPackets();
       message.decode(this.readBuf);
     } catch (err) { // Recovery failed
-    // TODO: throw different error indicating that reset failed, probably
-    // put inside resetMessage()
       this.nsi.disconnect();
-      errors.throwErr(errors.ERR_CONNECTION_CLOSED);
+      const newErr = errors.getErr(errors.ERR_CONNECTION_CLOSED);
+      caughtErr.message = newErr.message +
+        "\nError recovery failed: " + err.message +
+        "\nOriginal error: " + caughtErr.message;
+      throw caughtErr;
     }
   }
 
@@ -153,7 +155,7 @@ class Protocol {
     } catch (err) {
       if (!this.connInProgress &&
           err.code !== errors.ERR_CONNECTION_CLOSED_CODE) {
-        await this._recoverFromError(message);
+        await this._recoverFromError(err, message);
       }
       throw err;
     } finally {